30 Rock‘s second live outing has just been upgraded from fun stunt to must-see TV, and here’s why: Community‘s Donald Glover has been recruited to appear in the April 26 episode playing the rather key role of, um, Tracy Jordan.

The gig marks a homecoming for Glover, who previously worked as a writer on 30 Rock. He also has made a handful of blink-and-you-missed-it cameos on the Emmy-winning comedy, including one that actually foreshadowed his live episode stint.

As Carlock reveals, a special extended version of Jordan’s classic Season 1 jingle, “Werewolf Bar Mitzvah,” actually features vocals by Glover. “Tracy wasn’t available, so Donald came in and [performed the extra material],” he explains. “I don’t think you can tell. It’s pretty remarkable. All the spoken stuff is Donald doing Tracy.”

Back to the live episode, the plot revolves around Kabletown’s decision to discontinue TGS as a live show. Liz and Jack welcome the move, since shooting canned episodes will be far less time consuming. Kenneth, however, “tries to convince everyone that live television is worth doing,” explains Carlock, “and he does that by taking us back through the history of TGS.” As a result, a good portion of the half-hour features newly-created “flashbacks to old shows, and our [cast] jumps around playing all of those old parts.”